Are there nail manifestations in hand, foot, and mouth disease?

Nail Manifestations in Hand, Foot, and Mouth Disease

Yes, nail manifestations are well-recognized complications of hand, foot, and mouth disease (HFMD), occurring weeks after the initial infection and presenting primarily as onychomadesis (nail shedding) and Beau's lines.

Clinical Presentation

Nail changes develop as a delayed complication, typically appearing 3-8 weeks after the acute HFMD illness resolves. The two main patterns include:

• Onychomadesis: Complete nail shedding from the proximal portion due to temporary nail matrix arrest 1, 2, 3
• Beau's lines: Transverse grooves across the nail plate indicating temporary growth disruption 2, 3

Both fingernails and toenails can be affected, though the pattern varies by individual 4.

Pathophysiology

The mechanism involves direct viral damage to the nail matrix, particularly by Coxsackievirus A6 (CVA6), which has emerged as the predominant causative agent. Research using RT-PCR has detected CVA6 directly in nail samples from affected patients, confirming viral invasion of nail tissue 5. This represents a shift from the traditional enterovirus A16 that historically caused most U.S. cases 2.

• Direct viral injury to the nail matrix is the primary mechanism 5
• Minor contribution from cutaneous lesions around the nail fold causing secondary matrix damage 5
• The nail matrix arrest is temporary and self-limited 4

Clinical Significance and Reassurance

These nail changes are benign and self-resolving, requiring only reassurance rather than treatment. This is critical for avoiding unnecessary interventions:

• Spontaneous complete healing occurs within weeks to months without intervention 4
• No antifungal or other pharmacologic therapy is indicated 1
• The finding should prompt retrospective consideration of HFMD if the initial illness was mild or unrecognized 1, 3

Important Pitfalls

Do not confuse post-HFMD nail changes with onychomycosis or other nail pathology requiring treatment. The key distinguishing features include:

• Temporal relationship: History of viral illness 3-8 weeks prior 1, 2
• Self-limited course: Progressive improvement without treatment 4
• Multiple nail involvement: Often affects several nails simultaneously 4
• Age group: Predominantly children under 5 years 2

Be aware that atypical HFMD presentations, particularly with CVA6, may include more severe cutaneous involvement in children with atopic dermatitis ("eczema coxsackium"), adult cases, and delayed palmar-plantar desquamation 1, 5. These atypical features may make the initial diagnosis less obvious, but the subsequent nail changes remain characteristic.

Management Approach

The standard of care is supportive management and parental education:

• Inform families at the time of acute HFMD diagnosis that nail shedding may occur weeks later 5
• Provide reassurance when nail changes appear that this is expected and benign 1, 3
• No laboratory testing or treatment is necessary for isolated post-HFMD nail changes 1
• Avoid unnecessary antifungal therapy, which is ineffective and inappropriate 1